The invention refers to an electromotive actuator for a central door locking system of a motor vehicle having a slide which is adjustable between two end positions and connected to the door lock in either position and which can be decoupled from the electric motor in the end position so that it can be adjusted manually between the end positions easily.
An electromotive actuator of this type is known from DE-OS 36 27 893. This actuator has the advantage compared with an electromotive actuator, for example known from DE-OS 32 10 923, that the slide can be smoothly manually adjusted from its end positions. In the actuator of DE-OS 32 10 923 the electric motor and the gear wheels of the gearing, which is arranged behind said electric motor, have to co-rotate to allow manual shifting of the slide.
The actuator shown in DE-OS 32 10 923 for a central door locking system of a motor vehicle does not only allow a central locking or unlocking of a motor vehicle door, but also provides a so-called theft protection. In a central door locking system for a motor vehicle which is equipped with a theft protection it is possible to lock and unlock the door lock from the outside. In principle this is also possible with a handle in the inside of the motor vehicle. However, if the theft protection is put into operation from the outside, it is no longer possible to unlock the door lock with the handle on the inside. This is meant to make it more difficult for thieves to get inside the motor vehicle. In other words, if the windshield of a motor vehicle was smashed in, it is not possible to unlock the door with the handle in the inside of the motor vehicle and to then open it. It is only possible to enter through the window.
In the electromotive actuator according to DE-OS 10 923, the theft protection is realized by locking the slide by a latch which can be shifted by a second electric motor against movement in the unlocking direction. This has various disadvantages. In case of theft or in the case that the handle is operated from inside the motor vehicle, parts within the actuator are exposed to a major force, which can be effected by the handle on said parts. If no damage is accepted, the parts have to be designed correspondingly strong. It is also disadvantageous that it is impossible to unlock a vehicle door, once the motor operating the latch does not work in the theft protection position, for any reason. Finally, a lost travel in the gearing must be provided between the first electric motor, which is actuable, in principle, for locking in the reversed direction of rotation as well as for unlocking, in order to ensure that the blockage of the slide has been removed when the first motor engages in the slide.
Thus, the object of the invention is to create an electromotive actuator for a central door locking system providing theft protection without parts of the actuator being excessively strained in a theft attempt, and in which manual unlocking is also possible from the outside, even if the theft protection cannot be reset by the motor.